About the IPC/WHMA-A-620E standard
The IPC/WHMA-A-620B describes the requirements to produce cable assemblies and everything that goes with them. These include materials, methods, tests and acceptance criteria for the production of crimped, mechanically fastened or soldered connections and the associated assembly operations. If a cable assembly is produced according to one of the described methods, the quality is guaranteed. You can rely on this. Within this standard, the acceptance criteria are clearly divided into target, acceptable and defect.
Target
This is a result that is almost perfect. It is a desirable state, which is not always achievable, and may not be necessary to ensure the reliability of the assembly in its operating environment.
Target - Class 1,2,3
- Wire conductor ends are cut perpendicular to the wire longitudinal axis.
- All of the strands of the strand group are the same length.
- Wires are not scraped, nicked, cut, flattened, scored, or otherwise damaged.
Acceptable
This indicates a result that, although not necessarily perfect, guarantees the quality and reliability of the assembly for the relevant use.
Acceptable – Class 1,2,3
- Strand groups cut approximately perpendicular to the wire end.
- All of the strands of the strand group are approximately the same length.
- Attached burrs that will not be dislodged during process or operation.
- Acceptable – Class 1
Process Indicator - Class 2,3
- Strands cut, broken, scraped or severed if the number of damaged or broken strands in a single wire does not exceed the limits.
Defect
This result does not meet the acceptance criteria and negatively affects the form, fit or function of the assembly in its final use. As a manufacturer of cable assemblies, we are obliged to document every defect. Defect - Class 1,2,3
- Variation in strand length within a strand group that prevents installation to the full depth of the crimp contact area.
- Damaged strands exceed the limits.
To give you an idea of what we look for according to this standard, we give a few examples.
Length determination
A seemingly simple example is determining the length of the assembly. Between which points do we measure the length? When using contacts or open ends, we measure from the end. When using terminals, we measure from the centre of the terminal connection. The measured lengths must comply with the prescribed tolerances.
Marking and legibility
Also when marking, certain criteria must be met, such as legibility, position and influence on the electrical properties. For example, markings must be legible without magnification, clear, of equal height, and of a colour that contrasts with the background. The marking process must also not damage the product or impair its function in the intended application. An example of this is a laser print on the cable sheath, where the insulation has become more than 20% thinner at that spot.
Cable stripping
Stripping of wire and cable is another important point of attention. For example, the insulation must be stripped straight. With flexible wire or shielding, only a set number of strands may be missing from the connection.
Crimping contacts
When crimping contacts by machine or manually, it is important that the transition between the insulation and the conductor is centred within the inspection window. The strain relief grips the insulation perfectly, and the wire fits far enough, but not too far, into the contact.
There are numerous other criteria that we evaluate to produce high quality cable assemblies for long-term use for you. Would you like to experience for yourself how perfectly our cable assemblies are produced and finished? Then contact us without obligation and challenge us.
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